What will happen??
No one will have the BTC address. Hence will them isolated?
In FIAT, people can handover money to someone.. So, i predict BTC will be disappeared gradually.
Persons that will die and they did not use their coins on their wallet will eventually become waste and will not circulate in the market. If you have a person that you have known for a very long time that is dying then just ask this person to pass his/her coins to your wallet in order for this remaining coins to be still usable in the market.